CVE-2026-34839CWE-200CWE-306CWE-942

Glances Vulnerable to Cross-Origin Information Disclosure via Unauthenticated REST API (/api/4) due to Permissive CORS

High · published April 20, 2026

CVSS v4.0
7.7
EPSS
0%
Percentile
39.8
In the wild
Unconfirmed
What it is

Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.4, the Glances web server exposes a REST API (`/api/4/*`) that is accessible without authentication and allows cross-origin requests from any origin due to a permissive CORS policy (`Access-Control-Allow-Origin: *`). This allows a malicious website to read sensitive system information from a running Glances instance in the victim’s browser, leading to cross-origin data exfiltration. While a previous advisory exists for XML-RPC CORS issues, this report demonstrates that the REST API (`/api/4/*`) is also affected and exposes significantly more sensitive data. Version 4.5.4 patches the issue.

The record
Technical detail
CVSS v4.0
7.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
EPSS
0.00471 · 39.8th percentile
Weaknesses
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor; CWE-306 · Missing Authentication for Critical Function; CWE-942 · Permissive Cross-domain Security Policy with Untrusted Domains
Published
2026-04-20T23:09Z
EPSS history
Timeline
  • 20 APR 23:09Z
    Glances Vulnerable to Cross-Origin Information Disclosure via Unauthenticated REST API (/api/4) due to Permissive CORS
    cvelistv5